how to make a java main menu loop after using a case

To create a main menu loop in Java that continues to display the menu after a case has been executed, you can use a while loop or a do-while loop.

Here is an example of how you can use a while loop to create a main menu loop:

Scanner sc = new Scanner(System.in);
int choice;

while (true) {
    // Display the menu
    System.out.println("1. Option 1");
    System.out.println("2. Option 2");
    System.out.println("3. Option 3");
    System.out.println("4. Exit");
    System.out.print("Enter your choice: ");

    choice = sc.nextInt();

    switch (choice) {
        case 1:
            // code for option 1
            break;
        case 2:
            // code for option 2
            break;
        case 3:
            // code for option 3
            break;
        case 4:
            System.exit(0);
        default:
            System.out.println("Invalid choice.");
            break;
    }
}

In this example, the while loop will continue to execute indefinitely until the user chooses to exit the program by selecting option 4. The switch statement is used to execute the appropriate code for each menu option.

Here is an example of how you can use a do-while loop to achieve the same result:

Scanner sc = new Scanner(System.in);
int choice;

do {
    // Display the menu
    System.out.println("1. Option 1");
    System.out.println("2. Option 2");
    System.out.println("3. Option 3");
    System.out.println("4. Exit");
    System.out.print("Enter your choice: ");

    choice = sc.nextInt();

    switch (choice) {
        case 1:
            // code for option 1
            break;
        case 2:
            // code for option 2
            break;
        case 3:
            // code for option 3
            break;
        case 4:
            break;
        default:
            System.out.println("Invalid choice.");
            break;
    }
} while (choice != 4);

In this example, the do-while loop will continue to execute until the user chooses to exit the program by selecting option 4. The switch statement is used to execute the appropriate code for each menu option, as in the previous example.

Keep in mind that you can use any other looping construct, such as a for loop, to create a main menu loop in Java. You can also add additional menu options and modify the code in the switch statement to suit your needs.